PROD-043 Add repository dependency hygiene automation

[rndrntwrk]

Canonical source: docs/release/github-project-production-backlog.md

Epic: Repository Governance, Review Automation, And OSS Housekeeping

• ID: PROD-043
• Title: Add repository dependency hygiene automation
• Type: improvement
• Priority: P1
• Scope: active
• Area: dependencies
• Description: Add automated dependency update flows for npm workspaces,
  GitHub Actions, and Docker surfaces so the repo does not drift into stale or
  unreviewable infrastructure.
• Acceptance criteria:
  • dependabot.yml exists and covers active package directories plus
    GitHub Actions
  • update groups are tuned to avoid review spam
  • the review policy for automated dependency PRs is documented
• Dependencies: PROD-039
• Source docs: external benchmark:
  HyperscapeAI/hyperscape/.github/dependabot.yml
• Suggested owner: infra
• Blocker class: quality-blocking